Burglar-alarm.



No. 788,788. PATENTED MAY 2, 1905.

. J. NASER.

BURGLAR ALARM.

APPLICATION FILED JULY 6 1904.

uAMEs NASEK NITED STATES Patented May 2, 1905.

JAMES NASER, OF WESTMINSTER, LONDON, ENGLAND.

BU RGLAR-ALARIVI.

SPECIFICATION forming part of Letters Patent No. 788,788, dated May 2, 1905.

Application filed July 6, 1904. Serial No. 215,465.

To (all: 1072 0721 212; may concern:

Be it known that I, JAMns NASER, a subject of the King of Great Britain and Ireland, residing at 305 St. J amess Court, \Vestminster, London, S. W., England, have invented certain new and useful Improvements in Burglar- Alarms, of which the following is a specification.

This invention relates to burglar-alarms of the wedge type, which notonly sound an alarm when an attempt is made to open the door, window, or the like, but at the same time form awedge adapted to resist such opening. Such alarms have hitherto been constructed from sheet metal, two plates being hinged together at an acute angle to form a wedge, the movement of one plate caused by an attempt to open the door to which it is applied causing an alarm-bell to ring, a third hinged plate or other medium transferring the movement to the trigger of the bell. Owing to the weakness of the sheet-metal construction, such alarms have to be made of inconvenient] y large dimensions to attain anything like practical strength, and even then they are very easily damaged and do not offer much resistance against a persistent attempt to open the door.

The object of the present invention is to provide a very strong burglar-alarm of the wedge type, which while being of comparatively small dimensions is yet effective both in giving the alarm and in entirely resisting any attempt to open the door.

The invention consists in an alarm of the wedge type comprising a wedge of solid or nearly solid material supported upon a baseplate carrying an alarm-bell, the wedge-block being attached to the plate and suitably guided in such a manner that it is capable of a slight sliding movement relatively thereto, so that when moved by the door or the like it actuates the trigger of the alarm-bell. Such block is also preferably formed on its inclined face with a roughened or other friction surface, and the base-plate is provided on its under surface with strong rearwardly-extending points.

The invention will now be described with reference to the accompanying drawings, in which Figure 1 shows a side elevation of a preferred form of burglar or other alarm. Fig. 2 shows a plan, and Fig. 3 shows an elevation partly in section.

In carrying out the invention according to one modification a strong base-plate a is provided with a spring-motor-aetuated or equivalent alarm-bell g at one end, while its other end is formed with two triangular side ears I), bent up at right angles to form guides. Between the guides 7) a very strong wedge-block c is inserted, the wedge being of solid or nearly solid material. It is free to slide slightly be tween the guides, the amount of movement being limited by a cross-pin (Z, passing transversely through a slot (4 (see Fig. 3) in the block and carried by the side guides 7). The slot 6 is made of sufficient length to enable the block or wedge c to be pushed far enough to release the trigger f of the bell r and may be of sufficient depth to enable the block to rest on the base-plate, so as to relieve the pin from all downward pressure. The inclined face of the block 0 is preferably cross-cut .or scored, as shown, or otherwise roughened to present a frictional surface to the door. The under surface of the base-plate is fitted with sharp strong studs it, extending rearwardly, so as to prevent the alarm sliding when an attempt is made to open the door.

In use the alarm is placed in close proximity to the door, Window, or the like, With the thin end of its wedge-block 0 under the edge of the door or other moving member. Any attempt to open the door causes the block to slide rearwardlyand to release the trigger f of the hell 7, and thereby sound an alarm.

Further attempted movement of the door,

however, only results in the door becoming firmly wedged, the strong solid block effectively resisting opening of the door and with out damage to itself. The solid form of block naturally enables comparatively small dimensions to he adopted. So long as the door is being pushed the alarm continues to ring, and

if wedged firmly it will not cease. Means may be provided, if desired, to retain the wedge in the ringing position even after the door has been closed again.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A burglar or similar alarm and door or like wedge comprising a block having a flat under face and an inclined upper face, a baseplate having side wings to form guides for the block, means for loosely securing the block between said wings to permit relative longitudinal movement and an alarm-bell on the base-plate having its trigger in contact with said block, substantially as described.

2. A burglar or similar alarm and doorwedge comprising a block having a flat under face and an inclined upper face, a base-plate having side wings inclined to conform to the shape of the block, said block having a transverse elongated hole therein, a pin passing through said hole and supported by the wings so as to permit relative longitudinal movement of the block and an alarm-bell on the base-plate having its trigger in contact with the block, substantially as described.

3. A burglar or similar alarm and door or like wedge comprising a wedge-shaped block having a roughened inclined surface, a baseplate having sidewings to form guides for said block, a transverse elongated hole through the block, a pin passing through said hole and supported by the guide-wings so as to permit relative longitudinal movement of the block, an alarm-bell on the plate having its trigger in contact with said block, and rearwardlyinclined spikes on the under surface of the base-plate, substantially as and for the purpose hereinbefore set forth.

In witness whereof I have hereunto set my hand in presence of two witnesses.

JAMES NASER.

Witnesses:

ALBERT E. PARKER, FRANoIs J. BIGNELL. 

